Method of producing dry yeast.



s'rarns; PATENT OFFICE.

EDMUND KOELITZ, or znHLnNnonF, BERLIN, GERMANY, Assmnon re s. orrnn-HEIMER, or nussnpnonr, GERMANY.- v

, a I METHOD OF PRODUCING DRY YEAST.

No Drawing.

I 4 To all whom it'may concern:

Be it known that I, EDMUND KOELITZ, a citizen o'f'the Empire of Germany,residing at Zehlendorf, Berlin, Germany, have invented a new and usefulMethod of Producing Dry Yeast, of which the following is aspecification.

This invention relates to a novel method of treating pressed grain yeastso as to conviable dry yeast have all proven unsatisfactory andconsequently the product was useless for commercial purposes. When 100cells ofthe wet pressed yeast capable of growth were dried, only from 7to 10 cells in the product were found to be still alive. So also therelatively high rice of production rendered a general use 0 this dryyeast im-- practicable.

I have succeeded in devising a method by -which up to 100 per cent. ofviable yeast cells may be obtained. I have arrived at the solution ofthis problem by the following considerations and conclusions: In generaltheiyeast has by no means the short life inherent in yeastused forbaking purposes.

On the contrary it is well. known that the yeast in a fwild state canlive for months without being destroyed by self-consumption or exteriorinfluences. It winters in vineyards and orchards and infectsthe'atmosphere so frequently as to produce a fermentation at every placewhere there exist suitable solutions of sugar. As this wild yeast ispermanently exposed to the atmosphere, it is to be presumed that thedrying of the several cells is effected very quickly, more particularlyon dry autumn da s. Furthermore it is to be noted that the 1ntrinsicvalue of the yeast for baking purposes depends not only upon itscontents of alcoholase but more particularly upon its faculty of quicklyforming the enzym. The stability of the alcoholase in a dry condition isgood. -As acids are injurious to the alcoholase, theyshould be avoidedas much aspossible in dry yeasts. Moreover as the alcohol is alsoinjurious to thealcoholase, the alcohol formed during the enrichment ofthe yeast with nutritive materials should be removed by aeration. Theless moisture.

there is contained in the yeast, the better its contents of alc'oholasewill be preserved.

Higher temperatures should be avoided in the process, since they favorthe formation of endotryptase, which reduces the fermenting power of theyeast. Asparagin, on the contrary assists in the formation of alcoholasein the living cell and is indispensable for the manufacture of dryyeast. Finally I'have observed, that only a good physiological conditionof the material, prior .to the drying, is essential for obtaining a gooddry yeast. In order to attain this condition, highly diluted solutionsof d-glucose, d-fructose, saccharose and maltose may be used. After theenrichment of the yeast with. these nutritive materials, a doseof'asparagin is added, whereupon the mixture is dried as rapidly aspossible.

Example: For the .productionof 250 kilograms of dry yeast, about 750kilograms of pressed yeast are required. The solution of sugar for thephysiologic freshening-np of the yeast required to be highly diluted andits concentration should .never exceed 2. Belling at most. The weight ofthe raw yeast should be in the proportion of 2:1 to the weight of thesugar. In this nutritive liquid, the raw yeast is thoroughly dissolvedvat atemperature of 19 centigrade, while being energetically agitated upto 12 or 15 hours in a well ventilated room. During this process, theyeast should not ferment,

but should. absorb the sugar by. diifusion,

The solution should remain as neutral as Patented July so, 1912.

possible and care should be taken, that also during ventilation, theyeast will/not become acidulated. If necessary, the acid should beneutralized by meansjri f a diluted.

solution of soda. During the ventilation,

the temperature may be slowly raised, but it should never exceed 25centigrade. After the lapse of from 12 to 15 hours, the yeast may beallowed to stand up to 10 hours, be-

fore it isseparated', or it may be at once separated. The separatedyeast is'well washed out and is then rapidly-compressed so strongly asto be rendered as dry as possible. The resultant pressed yeast is atonce carefully kneaded while adding a solution of asparagin in theproportion of about 5 grams of asparagin to 50 kilograms of yeast. Thekneaded yeast is rapidly formed into filaments and is finally dried ondrying frames, by means of a currentof cold air.

It is obvious that the dry yeast produced as described should be wellprotected from moisture. It is preferably kept in hermetically closedvessels containing. suitable hygroscopic agents.

I claim:

1. The herein described method of producing dry yeast, which consists infreshening up pressed grain yeast of commerce with a diluted sugarsolution while strongly agitating the yeast and ventilating the room,separating and washing out the freshenedup'yeast, pressing thewashed-out yeast as rapidly and strongly as possible, kneading thepressed yeast with a solution of asparagin, turning the kneaded yeastinto filaments and drying said filaments by means of a current of coldair.

2. The herein described method of producing dry yeast, which consists infreshen- .ing up pressed grain yeast of commerce with diluted solutionsof d-glucose, d-fructose, saccharose and maltose While stronglyagitating the yeast and ventilating the room, separating and washing outthe freshenedup yeast, pressing the washed-out yeast as rapidlyandstrongly as possible, kneading the pressed yeast with a solution ofasparagin, turning the kneaded yeast into fila-.

ments and drying said filaments by means of a current of cold air.

3. The herein described method of producing dry yeast, which consists indissolving 2 parts by weight of pressed grain yeast of commerce in adiluted solution'of one part of sugar while energetically agitating.,the yeast and ventilating the room, also preventing the yeast fromacidifying, separating the treated yeast, washing out the separatedyeast', pressing the washed-out yeast as rapidly and strongly aspossible, kneadthe separated yeast, pressing the washed-out yeast asrapidly and strongly as possible, kneading the pressed yeast with asolution {of asparagin, turning the kneaded yeast into filaments, anddrying said filaments by means of a current of cold air.

EDMUND KOELITZ Witnesses:

WOLDEMAR HAUPT, HENRY HASPER.

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